Expression Blend, an ItemTemplate and an Implicit Style

Question

I'm having an issue with Blend not rendering items in a DataTemplate styled implicity.

I've setup a basic project to replicate the issue. Below is the Xaml + ResourceDictionary for those with Eagle eyes to see what I'm doing wrong (if anything) and if you're really keen theres a link to the Zipped project below.

This is what renders when the application is run:

Expected Output

and this is what Blend presents:

Blend Rendered

<Color x:Key="TextColor1">#FF3631C4</Color>

<Style TargetType="{x:Type TextBlock}">
    <Setter Property="TextWrapping" Value="NoWrap"/>
    <Setter Property="TextTrimming" Value="None"/>
    <Setter Property="Foreground">
        <Setter.Value>
            <SolidColorBrush Color="{DynamicResource TextColor1}"/>
        </Setter.Value>
    </Setter>
</Style>

<Canvas x:Name="LayoutRoot" DataContext="{Binding Source={StaticResource SampleDataSource}}">
    <TextBlock Text="Textblock" Canvas.Left="44.954" Canvas.Top="49.305" />
    <TextBlock Text="Textblock 2" Canvas.Left="44.954" Canvas.Top="86.284" />
    <ListBox ItemsSource="{Binding Collection}" Canvas.Left="134.016" Canvas.Top="29.026" Height="154.275" Width="384.575">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Property1}" />
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Canvas>

Complete Example Project (65kb) - WpfApplication2.zip

The problem can of course be solved by explictly setting the style, but in my main project this will cause a bit of a headache.

I've seen some comments on other posts around that Blend may have issues but nothing concrete.

Any thoughts / suggestions?

Thanks!

Edit:

I discovered that if I give my style an Explicit Key, I can then create an Implicit Style based on the Explicit like so:

<Style x:Key="TextBlockStyle1" TargetType="{x:Type TextBlock}">
    <Setter Property="TextWrapping" Value="NoWrap"/>
    <Setter Property="TextTrimming" Value="None"/>
    <Setter Property="Foreground">
        <Setter.Value>
            <SolidColorBrush Color="{DynamicResource TextColor1}"/>
        </Setter.Value>
    </Setter>
</Style>

<Style TargetType="{x:Type TextBlock}" BasedOn="{StaticResource TextBlockStyle1}" />

This then gives me the ability to add another Implicit Style as a Resource in my DataTemplate:

<DataTemplate>
    <DataTemplate.Resources>
        <Style TargetType="{x:Type TextBlock}" BasedOn="{StaticResource TextBlockStyle1}"></Style> 
    </DataTemplate.Resources>
    <TextBlock Text="{Binding Property1}" />
</DataTemplate>

This will then give me the blendability I'll need in my main Project but still doesn't quite answer my original question.

+1 For a well structured question :) – Vitalij Nov 09 '11 at 23:27 — Vitalij, Nov 09 '11 at 23:27

score 1 · Answer 1 · answered Nov 10 '11 at 01:01

Firstly Blend is written in WPF and XAML. So Blend has its own application style and as your application also defines global styles, in order not to merge them it will be applying them differently and there is probably a bug in the method they used to apply those styles.

This is my guess why this is happening. It doesn't solve the problem though, but might help you to find out other workarounds.

Expression Blend, an ItemTemplate and an Implicit Style

1 Answers1